Night sweats in men have several common causes, ranging from hormonal shifts and medications to sleep disorders and, less often, serious underlying conditions. Unlike simply feeling warm under heavy blankets, true night sweats involve episodes of sweating intense enough to soak through your clothes or sheets, regardless of room temperature. Understanding the most likely triggers can help you figure out whether yours are a minor nuisance or something worth investigating.
Low Testosterone and Male Hot Flashes
Most people associate hot flashes with menopause, but men experience them too. The trigger is declining testosterone, which can happen gradually with age or more abruptly after treatments like androgen deprivation therapy for prostate cancer. The thermal control center in the hypothalamus, the brain’s internal thermostat, becomes more sensitive when sex hormone levels drop. It misreads normal body temperature as too high and launches a cooling response: blood vessels in the skin widen rapidly, producing a flush of warmth, followed almost immediately by a cold, clammy sweat.
Testosterone levels naturally decline about 1% per year after age 30, so mild, occasional night sweats in middle-aged and older men often trace back to this gradual hormonal shift. Men undergoing prostate cancer treatment experience the most dramatic version, since those therapies suppress testosterone to near-zero levels. A blood test measuring total testosterone is the straightforward way to check whether hormones are playing a role.
Sleep Apnea
Obstructive sleep apnea is one of the most overlooked causes of night sweats in men, and it’s worth considering early because it’s both common and treatable. In a study of over 800 newly diagnosed sleep apnea patients published in the European Respiratory Journal, 31% reported frequent night sweats (three or more times per week), compared to just 11% of the general population. When your airway collapses repeatedly during sleep, your body ramps up its stress response to force you awake enough to breathe. That surge of adrenaline raises your heart rate, constricts blood vessels, and triggers sweating.
If your night sweats come with loud snoring, gasping during sleep, or daytime exhaustion that doesn’t improve with more hours in bed, sleep apnea is a strong possibility. Treatment with a continuous positive airway pressure (CPAP) device often reduces or eliminates the sweating along with the other symptoms.
Medications, Especially Antidepressants
About 10% of people taking an SSRI or SNRI antidepressant report excessive sweating as a side effect, and some studies using more careful assessment methods have found rates as high as 40% depending on the specific drug. This sweating often shows up at night. The effect isn’t limited to one class of antidepressant: SSRIs, SNRIs, tricyclics, and bupropion can all cause it. These medications alter the brain chemicals that regulate temperature alongside mood, which is why sweating is such a consistent side effect across the category.
Beyond antidepressants, other medications commonly linked to night sweats include drugs that lower blood sugar, hormone therapies, steroids, and some pain medications. If your night sweats started within a few weeks of beginning or changing a medication, that timing is a strong clue.
Alcohol and Blood Sugar Drops
Alcohol increases your heart rate and widens blood vessels in the skin, both of which promote sweating. Even a moderate amount of alcohol in the evening can disrupt your body’s temperature regulation overnight. For heavier drinkers, the effect is compounded: as your body processes alcohol while you sleep, a mild withdrawal state kicks in, producing clammy skin and drenching sweats. This is why people who drink regularly often notice the worst night sweats in the second half of the night, when blood alcohol levels are dropping.
Low blood sugar during sleep, called nocturnal hypoglycemia, is another metabolic trigger. It’s most common in people with diabetes who take insulin or certain oral medications, but it can happen in anyone. When blood glucose drops below about 70 mg/dL, the body releases stress hormones to raise it back up, producing hot, sweaty skin along with restlessness or vivid dreams. If you’re waking up drenched and shaky, or unusually hungry in the middle of the night, blood sugar is worth checking.
Anxiety and Nocturnal Panic Attacks
Chronic stress keeps your nervous system in a heightened state even during sleep, which can easily tip into sweating. But the more dramatic version is a nocturnal panic attack: you wake suddenly with a racing heart, difficulty breathing, and profuse sweating. These attacks happen during the transition between sleep stages and feel identical to daytime panic attacks, except you’re jolted out of sleep by them. They’re not caused by nightmares, and you may not feel anxious at all during waking hours.
Nocturnal panic attacks involve your brain’s fear-processing system misfiring during sleep. The result is a flood of adrenaline that triggers the same fight-or-flight response you’d have facing a real threat, including heavy sweating. If your night sweats come on suddenly, last only minutes, and are accompanied by a pounding heart or sense of dread, this is a likely explanation.
Infections
Night sweats are a well-known symptom of several chronic infections. Tuberculosis is the classic example, but other infections that can cause persistent, drenching night sweats include endocarditis (infection of the heart lining), HIV, brucellosis, bone infections (osteomyelitis), and certain fungal infections like valley fever. These infections trigger night sweats because your immune system is most active during sleep. The inflammatory chemicals your body releases to fight the infection reset your thermostat, producing fever followed by sweating as the fever breaks.
Infection-related night sweats typically come with other symptoms: fever during the day, unexplained weight loss, fatigue, or pain at the site of infection. Night sweats that appear alongside these symptoms, especially in someone with risk factors for TB or HIV, warrant prompt medical attention.
When Night Sweats Signal Something Serious
The concern most people have when searching this topic is whether night sweats could mean cancer, and the honest answer is: rarely, but it’s worth knowing the pattern. Lymphoma is the cancer most strongly associated with night sweats, where they’re classified as a “B symptom” alongside unexplained fever and significant weight loss. The specific descriptor oncologists use is “drenching sweats that require a change of bedclothes.” These aren’t damp-shirt episodes. They’re soaking, recurring, and they don’t have an obvious explanation like a warm room or a new medication.
Night sweats from lymphoma or another serious cause almost never appear in isolation. They come packaged with other red flags: losing more than 10% of your body weight without trying, fevers that come and go without infection, swollen lymph nodes you can feel in your neck, armpits, or groin, or persistent fatigue that doesn’t improve with rest. If your night sweats fit this pattern, that’s the scenario where getting evaluated quickly matters most.
Sorting Out the Cause
Because the list of possible triggers is long, narrowing it down starts with the basics. Consider timing first: did the sweats start after a new medication, a change in drinking habits, or a period of high stress? Those are the most common and most fixable causes. Think about accompanying symptoms next. Snoring and daytime sleepiness point toward sleep apnea. Low energy, reduced sex drive, and difficulty concentrating suggest low testosterone. Fever and weight loss raise the stakes and call for blood work and possibly imaging.
For most men, night sweats turn out to have a straightforward explanation: a medication side effect, a few too many drinks, untreated sleep apnea, or the gradual hormonal changes of aging. Keeping a brief log of when the sweats happen, how severe they are, and what you ate, drank, or took that day gives you and your doctor a much faster path to an answer than trying to sort it out from memory.